Description: Plants form spreading mats of chains of joints, rooting where they touch soil. Without tuberous central taproot. Stems segments: Joints with mostly six or fewer areoles per diagonal row across joint. Leaves: Usually bluish-green and over 7 mm long. Spines: Mostly three or fewer per areole, mostly only in upper areoles. Flowers: Usually pale yellow, often red in center, petals usually spreading widely.

Subspecies, varieties, forms and cultivars of plants belonging to the Opuntia macrorhiza group

Opuntia macrorhizaEngelm.: has only moderately glaucous stem segments that may reach 10 cm in length and diameter and basically yellow flowers.

Opuntia macrorhiza subs. pottsii(Salm-Dyck) U.Guzmán & Mandujano: has very glaucous compact stem segments reaching 5-6 cm in length and diameter, longer than wide, and distinctly stipitate. It is easily distinguished from other varieties of O. macrorhiza by its red flowers (as opposed to yellow), and very slender spines.

Bibliography: Major references and further lectures1) David J. Ferguson “Keys to the identity of cacti of the Albuquerque & Santa Fe area (Bernalillo, Sandoval, Santa Fe, Socorro, Torrance, and Valencia Counties)” November 1993 (updated May18, 2012)